Alcohols ** Flashcards
alcohols
have the general form of ROH and are named with the suffix -ol. If they are not the highest priority, they are given hydroxyl .
phenols
are benzene rings with hydroxyl groups. They are named for the relative positions of the hydroxyl groups. They are named for the relative positions of the hydroxyl groups. Ortho- adjacent, meta -separated by one carbon, para- on the opposite side of the ring
Alcohols can hydrogen bond, which can
raise their oiling points, and melting points relative to corresponding alkanes. Hydrogen bonding also increases the solubility of the alcohols.
Phenols
are more acidic than other alcohols because the aromatic ring can delocalize the charge of the conjugate base.
Electron-donating groups
like alkyl groups decrease acidity because they destabilize negative charges.
Electron-withdrawing groups
such as electronegative atoms and aromatic rings, increase acidity because they stabilize negative charges
Primary alcohols can only be oxidized by
PCC (pyridinium chloro-chromate.)
secondary alcohols can be oxidized to ketones
any common oxidizing agent
To make alcohols into better leaving groups, they are converted to
mesylates or tosylates
mesylates
contains the functional group -SO3CH3, which derive from methanesulfonic acid
Tosylates
contain the functional group SO3C6H4CH3 which derive from toluenesulfonic acid .
aldehydes and ketones can be protected by
converting them into acetals or ketals. Oter functional groups in the compound can be reacted (expecially by reduction) without effects on the newly formed acetal or ketal.
how are acetals formed
two equivalents of alcohol or dialcohol are reacted with the carbonyl. (a primary carbon with two -OR groups and a hydrogen atom)
How are ketals formed
two equivalents of alcohol or dialcohol are reacted with a carbonyl (a secondary carbon with two -OR groups)
deprotection
the acetal or ketal can be converted back to a carbonyl by catalytic acid
